The estimated number of patients included is at least 210, based on at least 10 centers with at least 20 patients each, which will be enrolled in an 18 months period. The power analysis was based on the following assumption: in order to use the powerful t-test for independent samples, a sample size equaling 105 patients in each group is sufficient to provide 95% statistical power to detect a difference of 5% in mean, for a type I error alpha = 0.05, and the population standard deviation = 10%. The difference in mean was based on previously published data which report an accuracy of approximately 80-85% for EUS-FNA, and 90% for contrast-enhanced EUS.